Chain tensioning device for continuous miner



y 1961 w. SILKS 2,982,529

CHAIN TENSIONING DEVICE FOR CONTINUOUS MINER Filed Oct. 28, 1959 s Sheets-Sheet 1 r 1 r a O V: 0 Q

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Walter Silks y 2, 1961 w. SILKS 2,982,529

' CHAIN TENSIONING DEVICE FOR CONTINUOUS MINER Filed Oct. 28, 1959 3 Sheets-Sheet 2 INVENTOR.

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Walter Silks CHAIN TENSIONING DEVICE FOR CONTINU- BUS MINER Walter Silks, Downers Grove, Ill., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Filed Oct. 28, 1959, Ser. No. 849,340

2 Claims. (Cl. 262-7) This invention relates to improvements in continuous mining machines of the boring type and more particularly relates to chain tensioning means for adjustable boring machines adjustable to mine coal seams of varying thicknesses.

A principal object of the invention is to provide a simplified and improved tensioning means for maintaining a uniform degree of tension on the trimmer chain of a boring machine, adjustable to operate in coal seams of varying thicknesses.

A further object of the invention is to improve upon the chain tensioning means of continuous mining machines of the boring type, in which a fluid pressure operated automatic take-up maintains the trimmer chain of the machine in uniform tension throughout the range of vertical adjustment of 'the machine, and in which an improved take-up connection is provided to the take-up idler for the trimmer chain.

' A further object of the invention is to improve upon the trimmer chain take-upsof adjustable cutting height boring types of mining machines in which ahydraulic cylinder and piston maintains a uniform tension on the trimmer chain, by providing an improved drive connection from the hydraulic cylinder and piston to the take-up idler for the chain, in the form of a capstan having the take-up cable wrapped therearound and clamped thereto.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherem:

Figure 1 is a front end view of a continuous mining machine of the boring type, illustrating one form the tensioning means of the invention may take; I

Figure 2 is an enlarged fragmentary detail end view of the machine, with certain parts broken away and certain other parts in section, illustrating certain details of the tensioning means not shown in Figure 1;

' Figure 3 is a fragmentary horizontal sectional view taken substantially along line 33 of Figure 2; and

Figure 4 is a diagrammatic view showing one form of hydraulic actuating circuit which may be employed to compensate for differences in movement between the upper and lower trimmer bars of the machine.

In the embodiment of the invention illustrated in the drawings, I have shown in Figure 1, a continuous mining machine of the boring type in which the boring heads and upper and lower trimmer bars for trimming the cusps left between the boring heads, are vertically adjustable to operate in varying thicknesses of seams of coal, rock or the like.

The boring machine as generally shown in Figure 1, includes a gear casing or cutter frame 11, mounted on and projecting forwardly from the main frame (not shown) of the machine, for vertical adjustment with respect thereto, and having spaced hubs 12 extending forwardly therefrom, forming supports for boring heads 13. The boring heads 13 have radial arms 15, having a central arcuate cutter 14 and radially outwardly spaced Patented May 2, 1961 arcuate cutters 16, 17 and 18 mounted thereon, the outer most cutters 18 being radially adjustable to adjust the boring head to the desired cutting height. The boring heads are driven from hollow shafts-1'9, journalled within the hubs 12, and driven in opposite directions from a suitable motor and reduction gearing (not shown), to drive the boring heads to progress and cut, broken down material toward the center of the machine.

The cutter frame 11 also forms a support for an upper cutter or trimmer bar, mounted on said'cutter frame on laterally spaced hydraulic jacks 21, operable to vertically adjust the trimmer bar 20 to the required cutting height of the machine, and to retain said trimmer bar in a selected adjusted cutting position.

The cutter frame 11 also forms a support for a lower 7 trimmer bar 23, shown as extending parallel to the upper trimmer bar 20 and supported .on a cutter frame 11 by hydraulic jacks 24 (Figure 2), depending from said cutter frame. The hydraulic jacks 24 are shown in Figure 2 as being spaced outwardly of the hydraulic jacks 21 and have connection with opposite end portions of the lower trimmer bar 23, to vertically adjust said trimmer bar with respect to the cutter frame 11 and to hold said trimmer bar in a selected position of adjustment.

The trimmer bars 20 and 23 have the usual endless cutter chain 25 guided for movement therealong for trimming the upstanding and depending cusps left be-- tween the boring heads .13. v I

The cutter chain 25 is trained about cornersprockets 26, at opposite ends of the lower trimmer bar 23 and extends angularly inwardly and upwardly therefrom, one run of said cutter chain 25 being trained about a drive sprocket 27, shown in Figure 3 as being splined or otherwise secured to a drive shaft 29, suitably journalled within a hub 30, extending outwardly from the front face of the gear casing or cutter frame 11, and driven from suitable drive gearing (not shown), enclosed within.

the cutter frame 11.

The opposite run of, the cutter chain 25 is trained about an idler sprocket 31, mounted on the cutter frame 11 on a shaft 32, extending forwardly from the front face of the frame 11. v

The two outer runs of the cutter chain 25 are trained about corner sprockets 33, at opposite ends of the cutter bar 20, and are guided for movement along said cutter 7 bar, to cut out the cuspsv depending from the mine roof between the boring heads 13.

Referring now to the tensioning means for maintaining a uniform tension on the cutter chain 25, in the various positions of adjustment of the trimmer bars 20 and 23 with respect to the cutter frame 11, a generally cylindaical capstan 35 is journalled on a reduced diameter portion 36 of the hub 30 on spaced bearings 37 and 39. A re tainer cap 40, secured to the outer end of the hub30,.

serves to retain said capstan in position on said hub.

The capstan 35 has a tension arm 41 extending gen-v erally radially therefrom having a tension idler 42 rotat-j ably mounted thereon and extending outwardly of said tension arm. The tension idler 42 has rolling tensioning engagement with the cutter. chain 25, and is maintainedin engagement therewith by a hydraulic jack 43, pivotally" connected to the lower trimmer bar 23 adjacent the outer end thereof, and a flexible cable 44 wrapped about the capstan 35 and clamped thereto.

The hydraulic jack 43 includes a cylinder 45, having spaced ears 46 depending from the head end thereof along opposite sides of a lug 47 projecting forwardly from the forward end portion of a trimmer bar support 48. The ears 46 are pivotally connected to said lug as by a transverse pivot pin 49.

The jack 43 also has a piston rod '50, having a connector 51 on its outer end, through which is trained one end 4 of the flexible cable 44 and turned back on itself to form a loop at the end thereof. A cable clamp 53 is provided to clamp the end of the flexible cable 44 to the body of the cable. The piston rod 50 may thus exert a take-up force on the flexible cable 44 upon retractable movement of the piston rod 50 within the cylinder 45 as fluid under pressure is admitted to the piston rod end of the cylinder 45.

The cable 44 extends upwardly from the connector 51 on the end of the piston rod 50 and around a direction changing sheave 55 mounted on a corner bracket 56 on a shaft 57. From the sheave 55, the cable 44 extends inwardly to the capstan 35 along the outside of an annular rib 59 extending radially therefrom, adjacent the inner end of said capstan. The cable 44 is then wrapped around the capstan for a number of turns, which may be two or three turns, and is clamped at its free end to a connector arm 60, extending tangentially of the capstan, by means of a cable clamp 61.

It may be seen from the foregoing that as the cable 44, wrapped around the capstan 35, is maintained under tension by operation of the hydraulic jack 43 to maintain the tension idler 42 into engagement with the cutter chain 25, that friction will be created between the flexible cable 44 and the capstan, and that a major portion of,

the rotational force exerted on the capstan will be through friction. This will reduce the pull on the connector arm 60 and cable clamp 61, and avoid the breakage that is common with hydraulic take-ups, where either a chain or a cable may be connected to the tensioning member.

It may further be seen that the hydraulic jack 43 moves vertically with the lower trimmer bar 23, and that the cable 44 extends upwardly therefrom around the direction changing device 55 and exerts a tangential force on the capstan, tending to tighten the cable thereto, and that the force on the capstan is always exerted in the same direction, regardless of the position of the lower trimmer bar 23 with respect to the cutter frame 11.

In Figure 4, I have shown an illustrative form of hydraulic circuit, which maintains pressure on the hydraulic jack 43 and maintains a uniform tension on the trimmer chain 25, regardless of the positions of adjustment of the upper and lower trimmer bars with respect to the cutter frame 11. As shown in this figure, a pump 63 supplies fluid under pressure to a relief valve 64, which may be set to relieve pressure from the cylinder of the jack 43 at a desired pressure and to accommodate the piston rod 50 to be extensibly moved therefrom by operation of the cable 44 when the tension on the chain is above a predetermined selected value, as when the trimmer bars 20 and 23 are adjustably moved outwardly with respect to the cutter frame 11. A pressure regulator valve 65 is provided in series with the relief valve 64 on the output side thereof and has connection with the piston rod of the jack 43 through a pressure line 66. The pressure regulator valve may be a fixed regulator valve which feeds hydraulic fluid under a constant pressure to the jack 43, to maintain a selected tension on the chain 25. The relief valve 64 and pressure regulator valve 66 may be conventional forms of relief and pressure regulator valves, so need not herein be shown or described further.

While I have herein shown and described one form in which may invention may be embodied, it should be understood that various variations and modifications of .4 the invention may be attained without departing from the spirit and scope of the novel concepts thereof, as defined by the claims appended hereto.

I claim as my invention:

1. In a chain tensioning device for the cutter chain of a continuous mining machine having a cutter frame, upper and lower trimmer bars mounted on said cutter frame for vertical adjustment with respect thereto, a cutter chain guided for movement about said trimmer bars, a drive spocket for said cutter chain rotatably mounted on said cutter frame, acapstan mounted for rotation about the axis of said drive spocket, a tension arm extending from said capstan having a tension idler thereon engageable with said cutter chain, a hydraulic jack pivotally connected to the lower of said trimmer bars and extending vertically therefrom and including a piston rod and valve means admitting fluid under pressure to said hydraulic jack to exert a fixed retractable force on said piston rod, a flexible cable clamped to said piston rod and extending upwardly therefrom, a direction changing device in alignment with the peripheral surface of said capstan about which said flexible cable is trained, said flexible cable extending inwardly from saiddirection changing device and being wrapped about said capstan a plurality of turns, a connector extending from said capstan, and means clamping said flexible cable to said connector to retain said flexible cable to said capstan, the frictional resistance between said flexible cable and said capstan relieving said connector and clamp from the forces required to maintain tension on said chain.

2. In a mining machine of the boring type having a plurality of boring heads for forming contiguous bores in a mine face in advance of the machine, a frame, upper and lower horizontally extending trimmer bars mounted on said frame immediately to the rear of said boring heads for vertical adjustment with respect thereto, an endless cutter chain trained along said trimmed bars, a drive sprocket and an idler sprocket rotatably mounted on said frame in an inwardly spaced relation with respect to opposite ends of said trimmer bars and between the latter, tensioning means for said cutter chain comprising a capstan pivotally mounted on said frame between said trimmer bars and in inwardly spaced relation with respect to the ends thereof, a tension arm extending from said capstan and having a tension idler thereon, engageable with said cutter chain, and means for maintaining said tension idler in tensioning engagement with said cutter chain comprising a hydraulic jack connected to one of said cutter bars, means maintaining fluid under pressure in said hydraulic jack to maintain a fixed retractable force thereon, a connector extending tangentially of said capstan, a flexible cable connected to said hydraulic jack at one end and to said connector at its opposite end and extending parallel to an adjacent side of said connector tangentially of said capstan and wrapped about said capstan a plurality of turns, and the frictional resistance between said flexible cable and said capstan relieving said connector from the forces required to maintain tension on said chain.

References Cited in the tile of this patent UNITED STATES PATENTS 2,901,230 Driehaus Aug. 25, 1959 

